Abstract
<jats:p> Three-dimensional (3D) tumor models exhibit drug responses that differ from conventional 2D cultures. However, how cellular metabolism dynamically evolves across culture models and during drug treatment remains poorly understood. We compared the responses of MCF-7 cells in 2D and 3D environments to 5-fluorouracil (5-FU), combining <jats:sup>1</jats:sup> H NMR cellular metabolomics with viable cell counts, the GLUT1-positive population, gene expression, ATP activity, and morphology. Principal component analysis revealed that culture dimensionality, rather than 5-FU treatment, was the primary driver of metabolic flux variation. 3D spheroids exhibited higher glycolytic flux at 72h. Importantly, this elevated glycolysis reflected a higher per-cell flux in larger spheroids rather than an increased cell number. We further observed a higher proportion of GLUT1-positive cells and increased HK2 expression in 3D culture, together with an epithelial phenotype characterized by increased CDH1 and decreased VIM expression. Functionally, 3D displayed maintaining higher cell viability, ATP activity following treatment. Together, these findings suggest that 3D architecture promotes a metabolically defensive phenotype and cellular metabolic behaviors is associated with morphology, which may inform future drug screening model selection. </jats:p>